The Editors and Readers of COMPUTE!
Atari DOS 2.0 Vs. 3.0
Can programs that require disks to be formatted in DOS 2.0 be formatted in DOS 3.0?
DOS 3.0 supports the enhanced storage space possible on the Atari 1050 disk drive, but will not work on the earlier 810 disk drive. Most software was written before the advent of the 1050 and was designed to use DOS 2.0. Some software includes DOS 2.0 on the disk. The problem is that a disk formatted in DOS 3.0 cannot be read from or written to by DOS 2.0. The reverse is also true. If the software boots up in DOS 2.0, it will not be able to read or write to your previously formatted DOS 3.0 disk. It may be possible to copy the software onto a DOS 3.0 disk. The software would boot up under DOS 3.0 and would be able to read and write DOS 3.0 disks (but not DOS 2.0-formatted disks). But you'll find this is almost impossible in practice, because most software is copy-protected. Since DOS 2.0 works just fine on the 1050 disk drive, stick with DOS 2.0 for most commercial software, and use DOS 3.0 for your own programming, if you like.
Because of various compatibility problems with DOS 3.0, Atari is considering replacing it with a new DOS dubbed 2.5 for development purposes. DOS 2.5 (or whatever it's called when released) may be available by this summer, and Atari is thinking about making copies available to current owners at little or no cost.